DragonFlyBSD

Attached test suite.

Please review the patch attached to
http://bugs.dragonflybsd.org/issue895. If there are no objections I
will commit it on Thursday, Jan 10.

It seems all BSDs leave select()'s timeout argument unchanged on
return (contrary to linux), so I don't intend anymore to "fix" dfly
with that respect.

Cheers,
Nicolas

:
:Please review the patch attached to
:http://bugs.dragonflybsd.org/issue895. If there are no objections I
:will commit it on Thursday, Jan 10.
:
:It seems all BSDs leave select()'s timeout argument unchanged on
:return (contrary to linux), so I don't intend anymore to "fix" dfly
:with that respect.
:
:Cheers,
:Nicolas

It looks reasonable after a quick perusal.

select()'s timeout argument is always left unchanged.  Linux originally
    adjusted it on return but I was under the impression that they
    reverted back to the BSD method of not touching it.  The changing of
    the timeout argument was a major mistake that linux made in their
    implementation a long, long time ago.

-Matt

Don't forget to add the hook to the Linux emulation layer for this system call.

Thanks for the remark. I completely forgot linux emulation. The
pselect syscall was introduced in linux 2 years ago:

http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.23.y.git;a=commit;h=9f72949f679df06021c9e43886c9191494fdb007

pselect() is still implemented by a wrapper in glibc though, at least
for debian 4.0. I'll try to implement the hook anyway.

Additionally, reading the linux pselect commit log revealed what
looks like a bug in my patch: if pselect() is interrupted by a signal
that was blocked prior to the call and unblocked by pselect(), the
syscall is interrupted but the signal handler is not called because
the patch restores the original mask before userret() is called.
pselect() should probably be implemented like sigsuspend() instead.

Here is a new version of the patch that restores the original signal mask only
after executing signal handlers (if any). This is similar to what is done in
sigsuspend() and deals correctly with the case where pselect() is interrupted by
a signal blocked in the original mask.

Committed to HEAD.

I discovered that DragonFly emulate linux 2.4.z but pselect was
introduced in linux 2.6.z. Furthermore, even recent distros (fedora
core 8) still implement pselect as a wrapper in glibc. So I can't
really add the pselect emulation hook for the time being.

Cheers,
Nicolas